1. Field of the Invention
The present invention relates generally to safety valve devices for use in high-pressure fluid applications. More particularly, the present invention is directed to an adjustable safety valve assembly incorporated into high-pressure and high-flow pneumatic and hydraulic fluid lines and which, upon experiencing an unregulated and excessive air flow through the line, causes a spring-biased bearing member within the valve to actuate to a closed/interrupted position.
2. Description of the Prior Art
Air flow and fluid flow shut off valve assemblies are fairly well know in the art. The purpose for such safety valves is typically to automatically shut off the air flow within the fluid line upon a predetermined air pressure being achieved, typically caused by a break or failure in the regulating equipment associated with the air compressor or air delivery source.
A first example of such an air pressure relief valve is illustrated in U.S. Pat. No. 5,623,962, issued to Danzy et al., and which includes a body with first and second openings for connection in an air line and an interior wall defining a flow-through passageway extending from a first opening to a second opening. A chamber with an inlet port and an outlet provides fluid communication between the chamber and the passageway. A guide is removably secured to the body and defines a bore extending into the chamber. The guide is spring-loaded and an adjustment screw is threadably secured to the open-ended portion of the guide and bears against the spring for adjusting the compression of the spring and, accordingly, the set pressure of the valve.
A further example of an air spring arrangement is disclosed in U.S. Pat. No. 6,056,277, issued to Wode, which teaches an air spring arrangement for a valve and in which a cylinder includes a chamber in which is mounted an axially movable and hollow piston. In an open position of the hollow piston, the valve clears the connecting line. In a closed position of the piston, the connecting line is blocked.
U.S. Pat. No. 4,930,553, issued to Grillo, discloses a further variation of a pressure relief valve having a poppet member biased toward and sealingly engaging a slidable tubular valve seat having unrestrained axial rotation and a central relief flow passage. When the system pressure reaches a threshold pressure the valve seat and poppet are both axially displaced such that at the moment the poppet is unseated from the valve seat, the valve seat is in motion. The motion of the valve seat when the poppet is unseating or reseating allows the valve seat to comply with any eccentricities of the poppet to achieve uniform seat stresses and low leakage rates as well as acceptable flow rates and low hysteresis.
U.S. Pat. No. 4,706,705, issued to Lee, II, discloses a miniaturized check valve having a generally tubular body including a cylindrical base and a guide sleeve of reduced diameter which axially extends from the base. The body forms an interior valve seat which surrounds an axially extending fluid passageway. The guide sleeve has a plurality of angularly spaced discharge openings and a pair of pilot orifices which are axially spaced from the valve seat. A valve ball is displaced from the valve seat to form a fluid flow path which extends generally axially through the valve seat and into the guide sleeve and thereafter generally radially through the orifices and openings for flow exteriorly of the guide sleeve. The ball is biased by a spring assembly which comprises a pair of axially aligned springs having a relatively low preload force and. low spring rate.
Finally, the Industrial Sales 2000 Source Book catalog discloses a pneumatic check valve (SV802, SV803 and SV804) produced by Coilhouse Pneumatics. The Coilhouse check valve is incorporated into a high pressure fluid line and includes a substantially tubular outer body having a first openable end with a threadably engageable cap (inlet end) and a second substantially narrowed end defined by annular shaped end wall with an interiorly threaded aperture defined therethrough (outlet end). The engageable cap also includes an interiorly threaded aperture which, in combination with the likewise threaded aperture at the outlet end, provides for a pressurized air input hose and an output hose to be attached to the check valve.
The shut off assembly within the Coilhouse check valve is provided by a nylon constructed seating member which is generally cylindrical in shape and axially recessed on its inlet side. A single coil spring exerts a biasing force on the outlet side and biases the seating member in a direction towards the inlet side. Upon experiencing a determined degree of pressurized air flow, the seating member is actuated in a direction against the spring, towards the outlet side of the valve housing, and shuts off the air flow upon the seating member shouldering against an associated and abutting interior end wall of the valve housing.
The present invention is a flow shut off valve for use with a pressurized fluid application and which acts to substantially shut off the fluid flow upon the occurrence of an opened and unregulated fluid flow and which exceeds a maximum flow rating permitted by the valve. The shut off valve of the present invention is further a significant improvement over the prior art in that it is particularly directed to actuating in response to a determined fluid flow (typically measured in cubic feet per minute xe2x80x9cCFMxe2x80x9d) rather than a determined fluid pressure (pounds per square inch xe2x80x9cPSIxe2x80x9d). It has been found that large and unregulated fluid flow output, even in the absence of significantly high pressure, can still pose significant danger to both users and other individuals in proximity to the fluid application and for which a suitably constructed shut off valve is required.
The shut off valve includes a substantially cylindrical housing interposed between a fluid supply outlet and an inlet of a flexible and elongated conduit. Typically secured to an opposite end of the conduit is any conventional type of fluid (air or hydraulic) powered tool.
The housing defines an axially extending interior communicating the fluid supply and conduit and which. The extending interior includes, at an intermediate location, an annular shoulder which separates an enlarged diameter portion with a narrowed diameter portion.
A seating member is slidably mounted within the enlarged diameter portion and is axially translatable over a selected distance defining an open position permitting fluid flow through the interior and a closed position in which the seating member abuts against the annular shoulder and substantially interrupts the fluid flow. The seating member further includes a substantially cylindrical shaped body with a substantially centrally disposed aperture facing an inlet end of the valve housing. A plurality of additional apertures are defined in annular spaced fashion around a circumference of the cylindrical shaped body and communicate the inlet end and an outlet end of the valve housing. The seating member further includes a closed end face at the outlet end.
A first spring is contained within the housing and exerts against an inlet side of the seating member. A second spring is likewise provided and exerts against an outlet side. The second spring is adjustable in its intensity through the provision of an insert sleeve threadably engaged within the narrowed diameter portion of the valve housing and which acts against an associated and abutting end of the second spring.
The force exerted by the second spring equalizes a combined force provided by the first spring and the normally regulated fluid supply in the open position. Upon the fluid application switching from a normally regulated condition to an opened and unregulated condition, the combined force acting upon the seating member overcomes the biasing force of the second spring and actuates the seating member to the closed position.
An additional advantage of the flow shut off valve includes a plurality of radially extending notches defined within an exterior surface of the closed end face of the seating member for maintaining the conduit in an inflated position upon said seating member actuating to the closed position and by permitting a reduced volume of fluid flow across the inlet side, through through notches, across the outlet side, and into the extending conduit. The ability to maintain the conduit in a semi-inflated position allows for quicker return time to the given pressurized fluid application and once the fluid supply returns to the regulated position and the valve reseats to the open position.